This present invention relates to a method and system that uses a digital image processing technique to examine cotton web homogeneity and monitor the operation of production equipment. Hence the invention is pertinent to the technical field of promoting production efficiency and product quality. The purpose of examining the homogeneity of cotton webs is to find the variations in density and the weight per unit area (called basic weight) in a production period to see if any abnormal operations occur. If the basic weight varies slightly, cotton webs has better homogeneity. Hence the quality of cotton webs can be promoted by controlling its homogeneity. The inspection methods according to a prior art are generally divided into two groups:
1. Detect the thickness of cotton webs by floating pressurized rollers and convert measured thickness data into weights and then examine the variations in weight. One of the disadvantages of such a method is that the direct contact between rollers and cotton webs may cause damages to cotton webs, in particular, in a lightweight cotton web test.
2. Detect homogeneity by radioactive rays (xcex1 rays or xcex2 rays). The radioactive rays are detrimental to human bodies and so most tests use spot measurement to evaluate the homogeneity of cotton webs. Generally homogeneity is judged by weights per unit area. Weight changes on spots do not have sufficient representation for the variations in the whole area. Thus it affects the correctness of results.
In view of the above-mentioned problems, the homogeneity test method proposed by the inventor is a non-contact measurement one that eliminates the possibility of injury to the physical properties of cotton webs. Adjusting the aperture of cameras can change sampled areas. As a result the influence of local density variations on the evaluation of overall homogeneity can be minimized. Besides, the measurement correctness can be promoted and there is no harm to human bodies and physical properties of cotton webs.